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2 years ago

Which feature do all adult echinoderms have?

2 answers:

4 0

The common name to the family member of phylum Echinodermata of marine family is echinoderm. They are usually characterized by a five-fold symmetry, and possess an internal skeleton of calcite plates. They are found at every ocean depth.

The features of all adult echinoderm are:

- They have a five-fold symmetry.

- Body without segmentation.

- Spiny skin.

- Internal skeleton.

- found at every ocean depth.

BigorU [14]2 years ago

3 0

Mhmh they have smellytypes on their bodies so yeah

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Why do you think that the electrons are not shown?

snow_lady [41]

Because there to tiny to see

7 0

2 years ago

Which mineral(s) might you be examining if you place some hydrochloric (hcl) acid on a sample and it fizzes?

makvit [3.9K]

The minerals that one might be examining if you place some hydrochloric acid on a sample and it fizzes are Calcite and Dolomite.
Calcite and dolomite are very similar minerals. Both have the same hardness, the same rhombohedral cleavage, and are found in identical geologic settings. The best way to tell one from the other is the acid test; A drop of 1 M HCl on calcite produces an instant , obvious Fizz; a drop on dolomite produces slow or no obvious bubbling.

4 0

2 years ago

2. How many molecules are contained in 25 L of N₂ at S. T.P.?

irina [24]

Explanation:

How many nitrogen molecules are in 1 liter of nitrogen gas at STP?

Answer

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Pete Gannett

Ph.D. Chemistry, University of Wisconsin-Madison, (1982)2y

Seems to be an ideal gas law question. The relevant equation is:

PV = nRT

where P is the pressure in atmospheres, V is the volume in liters, n is the number of moles of gas, R is the gas constant (0.082 atm-L/mole-deg K), and T is temperature in Kelvins. STP means standard temperature and pressure and this is taken as 1 atm and 0º C or 273 K.

To calculate the number of molecules we will use the constant 6.023 * 10^23 molecules/mole and, therefore, we will need to know the number of moles (n). So, first we’ll rearrange the gas law equation, isolating ’n’ and then put the numbers in.

n = PV/RT = 1 * 1 / (0.082)(273) = 0.0447 moles

So, to calculate the number of molecules, multiple this by the number of molecules in a mole and you get:

# molecules of nitrogen in 1 Liter at STP = 6.023 * 10^23 molecules/mole * 0.0447 moles = 2.6905 * 10^22 molecules

Note, it does not matter what the gas is.

6 0

1 year ago

Read 2 more answers

When 1.0g of diethyl ether is converted to vapor at its boiling point, about how much heat is absorbed? (C4H10O, Hvap= 15.7kj/mo

Aloiza [94]

Answer:

Option D = 0.2 Kj

Explanation:

Given data:

Mass of diethyl ether = 1.0 g

Hvap = 15.7 Kj / mol

Heat absorbed = ?

Solution:

Q = mass × Hvap / molar mass

Q = 1.0 g × 15.7 Kj / mol / 74.12 g/mol

Q = 15.7 Kj / 74.12

Q = 0.212 KJ

8 0

2 years ago

In the reaction N2 + 3H2 → 2NH3, what is the mole ratio of hydrogen to nitrogen?

uranmaximum [27]

Answer: The mole ratio of hydrogen to nitrogen is 3 mole: 1 mole, 3:1

Explanation:

•Mole ratios are determined using the coefficients of the substances in the balanced chemical equation. •Each coefficient represents the number of mole of each substance in the chemical reaction.

•The mole ratio can be determined by first writing out a balanced chemical equation for the reaction.

For this reaction the balanced chemical equation is

N2(g) + 3H2(g) ----> 2NH3(g)

1mol:3mol : 2mol

From the equation we can see that 1 mole of N2(g) reacts with 3 moles of H2(g) or 3 moles of H2(g) react with 1 mole of N2(g) to produce 2 moles of NH3(g).

Therefore, the mole ratio of hydrogen to nitrogen is 3 mole: 1 mole, 3:1

7 0

2 years ago